S80: Wheels/Brakes strange occurance - electrical?

[fordlover]

XC70 D4 2015 , 46,000 miles. MOT due in 4 weeks.
40,000 mile service c/o @ 41,675 miles. 11 months ago.

long trek home yesterday from working away, 110 miles. all was going well, then after a brief stop at the late shop just 1.5 miles from home the car started acting up. first i got ECS error message, then ABS error message then the very serious looking BRAKE ! (red triangle) warning. then within about 200 yards of home the car seemed to 'stall' very briefly, then it kind of slowed as if in limp mode. i was down to about 20 miles of fuel so i initially thought it was a fuel probelm. i pulled to the kerb and gave it a little revving in park. seemed fine. so with just 200 yds to go i carried on. it got worse. anything above walking pace was accompanied by a very aggressive 'rattling/clattering' noise from somewhere around the front nearside wheel. immediately taking my foot off the accelerator the noise went away. all the warning lights on the dash were still on, now accompanied by the Tyre Pressure Level system light. I managed to coax the car car home and onto the drive. it was very late so i left it until this morning.
I popped the bonnet, couldn't see any sign of leaks or low fluids. underneath i fully expected to see something horrendous like a drive-shaft hanging off. nope, nothing. started her up, no warning lights. gingerly backed her off the drive, no issues. a little more bravely took her around the block, still nothing. ventured as far as the petrol station. no issues, gave her some diesel and returned home with no issues or warnings whatsoever.
I am thoroughy confused and worried. what could it be? what caused it? must be someting wrong somewhere. the rattling/chattering was quite visicous.

[FreshAir]

Could it be an ABS sensor or cable for ABS sensor so triggering things?

I don't know if tyre pressure monitoring is by pressure or ABS wheel count comparison on these.

[xavierx]

If your car is 4 wheel drive, and you have any ABS sensor related issue, the car will go MENTAL and start randomly braking individual wheels and engaging/disengaging the 4 wheel drive when you are at low speeds (which will explain any wheel clunking noise) as I found this out the hard way 1300 miles from home last year 🤣

To diagnose, in VIDA you can view the wheel speed in the BCM for each individual wheel and you will see one of them dropping out the zero when the rest of the sensors are showing the correct speed.

To be fair though in VIDA it will probably by this stage already tell you exactly which sensor is faulty, though in my case VIDA told me there was a "mechanical failure" with the tone-wheel. This was not the case for me, it was just the electronic sensor.


https://www.volvoforums.org.uk/showthread.php?t=335592

[fordlover]

''VIDA'' . . . . . what is that ?

[xavierx]

Oh sorry, it is the official/dealership diagnostic software for Volvos.

Basically it will show you more error codes / live data than the generic diagnostic code readers can.

You'll want a volvo specialist with VIDA, or a local helpful forum member, as many of us have it, to be able to tell you which sensor is causing the problem. It would be near impossible to just guess which one it is.

[fordlover]

ABS sensor issue is now sounding very likely, (thank you for both replies) i had a chat with my local mechanic who can't fit me in for a couple of weeks, but he also thinks it could be the ABS, from what i described. so i have booked it in elsewhere for a MOT + 6,000 mile service and will get them to check out the ABS fualt/diagnosis tthe same time. might get lucky and find the issue and get it fixed.

[Simmy]

you need to go to hallmark volvo specialists in stockport they wil diagnose and advise any course of intervention required to get it fixed at a very competitive price. i use this company to do the jobs i can no longer do as my health is slowly declineing